U.S. patent application number 16/028316 was filed with the patent office on 2019-05-09 for dust mitigation system utilizing conductive fibers.
The applicant listed for this patent is The Boeing Company. Invention is credited to Kavya K. Manyapu, Leora Peltz.
Application Number | 20190134644 16/028316 |
Document ID | / |
Family ID | 59897453 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190134644 |
Kind Code |
A1 |
Manyapu; Kavya K. ; et
al. |
May 9, 2019 |
Dust Mitigation System Utilizing Conductive Fibers
Abstract
A Dust Mitigation System ("DMS") is disclosed that includes a
fabric-material having a front-surface and a back-surface; a
plurality of conductive-fibers within the fabric-material; and a
plurality of input-nodes approximately adjacent to the back-surface
or the front-surface of the fabric-material. The plurality of
conductive-fibers are approximately parallel in a first direction
along the fabric-material and are approximately adjacent to the
front-surface of the fabric-material and the plurality of
input-nodes are in signal communication with the plurality of
conductive-fibers and configured to receive an alternating-current
("AC") voltage-signal from an input-signal-source. The plurality of
conductive-fibers are configured to generate an electric-field on
the front-surface of the fabric-material in response to the
plurality of input-nodes receiving the AC voltage-signal from the
input-signal-source and a traveling-wave (from the electric-field)
that travels along the front-surface of the fabric-material in a
second direction that is transverse to the first direction.
Inventors: |
Manyapu; Kavya K.;
(Friendswood, TX) ; Peltz; Leora; (Pasadena,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Boeing Company |
Chicago |
IL |
US |
|
|
Family ID: |
59897453 |
Appl. No.: |
16/028316 |
Filed: |
July 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15199618 |
Jun 30, 2016 |
10016766 |
|
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16028316 |
|
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62312931 |
Mar 24, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B03C 3/41 20130101; B03C
3/60 20130101 |
International
Class: |
B03C 3/60 20060101
B03C003/60; B03C 3/41 20060101 B03C003/41 |
Claims
1. A Dust Mitigation System ("DMS") comprising: a fabric-material
having a front-surface and a back-surface; a plurality of
conductive-fibers within the fabric-material, wherein the plurality
of conductive-fibers are approximately parallel in a first
direction along the fabric-material and are approximately adjacent
to the front-surface of the fabric-material; and a plurality of
input-nodes approximately adjacent to the fabric-material, wherein
the plurality of input-nodes are in signal communication with the
plurality of conductive-fibers and configured to receive an
alternating-current ("AC") voltage-signal from an
input-signal-source, and wherein the plurality of conductive-fibers
are configured to generate an electric-field on the front-surface
of the fabric-material in response to the plurality of input-nodes
receiving the AC voltage-signal from the input-signal-source and a
traveling-wave, from the electric-field, that travels along the
front-surface of the fabric-material in a second direction that is
approximately transverse to the first direction.
2. The DMS of claim 1, wherein the plurality of conductive-fibers
are a plurality of carbon nanotube ("CNT") fibers and the plurality
of CNT-fibers are braided with the fabric-material.
3. The DMS of claim 1, further including a weave of the
fabric-material, wherein the fabric-material includes a plurality
of fabric-material welt threads, a plurality of fabric-material
warp threads, and a plurality of insulating threads, a sub-weave of
the weave of the fabric-material, wherein the sub-weave includes
the plurality of conductive-fibers, the plurality of insulating
threads, and the plurality of fabric-material welt threads, wherein
the plurality of insulating threads are spaced in-between the
plurality of conductive-fibers.
4. The DMS of claim 3, wherein the plurality of conductive-fibers
are a plurality of carbon nanotube ("CNT") fibers.
5. The DMS of claim 4, wherein the plurality of CNT-fibers are
configured as a series of approximately parallel CNT-fibers along
the fabric-material in the first direction.
6. The DMS of claim 1, further including an input-signal-source in
signal communication with the plurality of conductive-fibers.
7. The DMS of claim 6, wherein the input-signal-source is a
three-phase input-signal-source.
8. The DMS of claim 6, further including a DMS controller in signal
communication with the input-signal-source.
9. The DMS of claim 8, wherein the input-signal-source is
configured to produce the AC voltage-signal having a plurality of
AC phased-signals that are transmitted to the plurality of
input-nodes and wherein a voltage, frequency, and phase of each AC
phased-signal, of the plurality of AC phased-signals, is fixed or
individually varied by a DMS controller.
10. The DMS of claim 9, further including a plurality of sensors
within the fabric-material, wherein the plurality of sensors
produce a plurality of sensor data signals, wherein the plurality
of sensors are in signal communication with the DMS controller, and
wherein the DMS controller is configured to receive the plurality
of sensor data signals and, in response, adjust the voltage,
frequency, and phase of each AC phased-signal, of the plurality of
AC phased-signals.
11. The DMS of claim 10, further including a plurality of actuators
within the fabric-material.
12. The DMS of claim 11, wherein the actuators are in signal
communication with the DMS controller and wherein the DMS
controller is configured to produce an actuation signal that is
transmitted to the plurality of actuators in response to the DMS
receiving the plurality of sensor data signals.
13. The DMS of claim 6, wherein the plurality of conductive-fibers
are a plurality of carbon nanotube ("CNT") fibers and wherein the
fabric-material is an ortho-fabric-material.
14. The DMS of claim 13, further including a plurality of
thermoplastic-fibers mounted on the fabric-material creating a
micron-sized insulating layer.
15. The DMS of claim 6, wherein the plurality of conductive-fibers
are a plurality of carbon nanotube ("CNT") fibers and wherein the
plurality of CNT-fibers includes a first plurality of CNT-fibers
and a second plurality of CNT-fibers, and wherein the first
plurality of CNT-fibers is oriented in a first direction and the
second plurality of CNT-fibers is oriented in a second direction
that is different than the first direction.
16. The DMS of claim 15, wherein the first plurality of CNT-fibers
is superimposed on the second plurality of CNT-fibers.
17. The DMS of claim 6, wherein the plurality of conductive-fibers
are a plurality of carbon nanotube ("CNT") fibers and wherein the
plurality of CNT-fibers includes a first plurality of CNT-fibers
and a second plurality of CNT-fibers, wherein the first plurality
of CNT-fibers has a first spacing between CNT-fibers in the first
plurality of CNT-fibers, wherein the second plurality of CNT-fibers
has a second spacing between the CNT-fibers in the second plurality
of CNT-fibers, and where the second spacing is different than the
first spacing.
18. A method for mitigating dust with a dust mitigation system
("DMS"), wherein the DMS includes a fabric-material having a
front-surface and a back-surface, a plurality of conductive-fibers
within the fabric-material in a first direction along the
fabric-material, and a plurality of input-nodes in signal
communication with the plurality of conductive-fibers, the method
comprising: receiving an alternating-current ("AC") voltage-signal
from an input-signal-source at the plurality of input-nodes;
generating an electric-field on the front-surface of the
fabric-material with the plurality of conductive-fibers; and
generating a traveling-wave, from the electric-field, that travels
along the front-surface of the fabric-material in a second
direction that is approximately transverse to the first
direction.
19. The method of claim 18, wherein receiving the AC voltage-signal
includes receiving at least one sensor data signal from at least
one sensor within the fabric-material, wherein the sensor data
signal indicates if any dust particles are on a shield of the DMS
and producing the AC voltage-signal based in response to receiving
the at least one sensor data signal.
20. The method of claim 19, further including producing a vibration
on the fabric-material based on the at least one sensor data
signal.
Description
CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY
[0001] The present patent application is a continuation of U.S.
Nonprovisional application Ser. No. 15/199,618, filed on Jun. 30,
2016, entitled "Dust Mitigation System Utilizing Conductive
Fibers," to Kavya K. Manyapu et al., which issued as U.S. patent
Ser. No. 10/016,777 on Jul. 10, 2018, which nonprovisional
application claims priority under 35 U.S.C. .sctn. 119(e) to
earlier filed U.S. provisional patent application No. 62/312,931,
filed on Mar. 24, 2016, and entitled "Dust Mitigation System
Utilizing Carbon Nanotube Fibers," both of which applications are
hereby incorporated herein by this reference in their
entireties.
BACKGROUND
1. Field
[0002] The present disclosure relates to dust mitigation, and more,
particularly to a dust mitigation system utilizing
conductive-fibers.
2. Related Art
[0003] Exploration activities preformed on the Moon by both humans
and robotic spacecraft occur on a planetary surface that is
comprised of unconsolidated fragmental rock material known as the
lunar regolith. The lunar surface is covered by several layers of
thick regolith formed by high-velocity micrometeoroid impacts, and
is characterized by the steady bombardment of charged atomic
particles from the sun and the stars. The lunar regolith includes
rock fragments and, predominantly, much smaller particles that are
generally referred to as lunar soil. From the time of their first
interactions with the lunar soil, the NASA Apollo astronauts
reported that the lunar soil contained abundant small particles,
which have been referred to as "lunar dust" (or just "dust"). This
dust had caused several anomalies during the Apollo missions
because of the lunar dust's strong tendency to collect on, adhere
to, or otherwise contaminate the surface of equipment that were
utilized in extravehicular activity ("EVA") operations. Today,
lunar dust is formally defined as "lunar soil" particles that are
smaller than 20 .mu.m in diameter; however for the purposes of this
disclosure the term "lunar dust," "lunar soil," or "dust" may be
utilized interchangeably.
[0004] Additionally, the Apollo mission also exposed the ability of
lunar dust to rapidly degrade spacesuits and impact the mission
operations. As an example, the Apollo technical crew debriefings
and post-mission reports include numerous references by the Apollo
crews to the effects of lunar dust on a range of systems and crew
activities during lunar surface operations. Among the EVA systems
that were mentioned frequently by the crews in relation to possible
lunar dust effects were the Apollo spacesuits that were worn during
lunar surface operations. These effects included: 1) dust adhering
and damaging spacesuit fabrics and system 2) mechanical problems
associated to lunar dust that included problems with fittings and
abrasion of suit layers causing suit pressure decay 3) vision
obscuration; 4) false instrument readings due to dust clogging
sensor inlets; 5) dust coating and contamination causing thermal
control problems; 6) loss of traction; 7) clogging of joint
mechanisms; 8) abrasion; 9) seal failures; and 10) inhalation and
irritation.
[0005] As an example, in FIG. 1 an image is shown of a NASA
astronaut 100 during the Apollo 17 mission weaver a lunar dust 102
coated spacesuit 104 after an EVA operation. Similarly, in FIG. 2
an image of a spacesuit 200 is shown with a hole (or rip) 202 in
the knee section of the spacesuit 200 that was caused by abrasion
due to the lunar dust. As such, there is a need for a system and
method to mitigate (i.e., remove or minimize) dust prior to sending
humans back to either the lunar surface or other similar planetary
surface. Moreover, there is also a need for to mitigate dust on
Earth because of dust exposed systems such as, for example,
flexible solar panels and other flexible systems that may be
clogged by dust.
[0006] At present, attempted solutions have proposed the
utilization of both active and passive methods that have been
mostly limited to utilization on rigid surfaces such as solar
panels, optical planes, glass structures and thermal radiators.
Unfortunately, applying these technologies for spacesuit dust
removal have remained a challenge due to the complexity of
spacesuit design that includes irregular contours of the spacesuit,
flexible structure of the soft areas of the spacesuit and
polytetrafluroethylene (as an example, TEFLON.RTM. produced by The
Chemours Company of Wilmington, Del.) coated spacesuit material. As
such, there is also a need for a system and method for mitigating
dust that is compatible with existing fabric-materials for
utilization in a spacesuit (for example ortho-fabric or emerging
new flexible materials) or other devices/systems utilizing
fabric-materials such as, for example, space habitats, inflatable
structures, flexible and/or deployable antennas, and flexible solar
panels.
SUMMARY
[0007] A Dust Mitigation System ("DMS") is disclosed. The DMS
includes: a fabric-material having a front-surface and a
back-surface; a plurality of conductive-fibers within the
fabric-material; and a plurality of input-nodes approximately
adjacent to the fabric-material. The plurality of conductive-fibers
are approximately parallel in a first direction along the
fabric-material and are approximately adjacent to the front-surface
of the fabric-material and the plurality of input-nodes are in
signal communication with the plurality of conductive-fibers and
configured to receive an alternating-current ("AC") voltage-signal
from an input-signal-source. The plurality of conductive-fibers are
configured to generate an electric-field on the front-surface of
the fabric-material in response to the plurality of input-nodes
receiving the AC voltage-signal from the input-signal-source and a
traveling-wave (from the electric-field) that travels along the
front-surface of the fabric-material in a second direction that is
approximately transverse to the first direction.
[0008] In an example of operation, the DMS performs a method that
includes receiving the AC voltage-signal from the
input-signal-source at the plurality of input-nodes, generating the
electric-field on the front-surface of the fabric-material with the
plurality of conductive-fibers, and generating the traveling-wave,
from the electric-field, that travels along the front-surface of
the fabric-material in the second direction that is at the pre-set
angle to the first direction.
[0009] Other devices, apparatus, systems, methods, features and
advantages of the disclosure will be or will become apparent to one
with skill in the art upon examination of the following figures and
detailed description. It is intended that all such additional
systems, methods, features and advantages be included within this
description, be within the scope of the disclosure, and be
protected by the accompanying claims.
BRIEF DESCRIPTION OF THE FIGURES
[0010] The disclosure may be better understood by referring to the
following figures. The components in the figures are not
necessarily to scale, emphasis instead being placed upon
illustrating the principles of the disclosure. In the figures, like
reference numerals designate corresponding parts throughout the
different views.
[0011] FIG. 1 is an image of a NASA astronaut having a spacesuit
contaminated with lunar dust after an EVA operation.
[0012] FIG. 2 is an image of a spacesuit with a hole in the knee
section of the spacesuit that was caused by abrasion due the lunar
dust.
[0013] FIG. 3A is side-view of a system block diagram of an example
of an implementation of a Dust Mitigation System ("DSM") in
accordance with the present disclosure.
[0014] FIG. 3B is a top-view of a system block diagram of the
implementation of the DMS (shown in FIG. 3A) in accordance with the
present disclosure.
[0015] FIG. 4 is a top-view of an implementation of a weave of the
fabric-material with the plurality of conductive-fibers (shown in
FIGS. 3A and 3B) in accordance with the present disclosure.
[0016] FIG. 5A is an amplified front-view of an example of an
implementation of the weave shown in FIG. 4 for an
ortho-fabric-material with a plurality of conductive-fibers in
accordance with the present invention.
[0017] FIG. 5B is a less amplified front-view of the weave shown in
FIG. 5A for the ortho-fabric-material with the plurality of
conductive-fibers in accordance with the present invention.
[0018] FIG. 5C is a back-view of the weave shown in FIGS. 5A and 5B
in accordance with the present disclosure.
[0019] FIG. 6 is an angled side-view of an example of an
implementation of a portion of two conductive-fibers in accordance
with the present disclosure.
[0020] FIG. 7A is an amplified front-view of an example of an
implementation of the insulation of the plurality of
conductive-fibers on the front-surface of the fabric-material in
accordance with the present disclosure.
[0021] FIG. 7B is an amplified front-view of an example of an
implementation of an insulating layer on the front-surface (shown
in FIG. 7A) of the fabric-material in accordance with the present
disclosure.
[0022] FIG. 7C is an amplified front-view of an example of an
implementation of a top-layer coating on the front-surface (shown
in FIGS. 7A and 7B) of the fabric-material in accordance with the
present disclosure.
[0023] FIG. 8 is an amplified front-view of an example of another
implementation of an ortho-fabric-material with a first plurality
of carbon-nanotube ("CNT") fibers and second plurality of
CNT-fibers in accordance with the present disclosure.
[0024] FIG. 9 is an amplified front-view of an example of yet
another implementation of an ortho-fabric-material with a first
plurality of CNT-fibers and second plurality of CNT-fibers in
accordance with the present disclosure.
[0025] FIG. 10 is a front-view of an example of still another
implementation of an ortho-fabric-material with a first plurality
of CNT-fibers and second plurality of CNT-fibers in accordance with
the present disclosure.
[0026] FIG. 11 is a front-view of an example of an implementation
of an ortho-fabric-material with a plurality of CNT-fibers driven
with multiple electrical waveforms in accordance with the present
disclosure.
[0027] FIG. 12 is a front-view of an example of an implementation
of an ortho-fabric-material with a plurality of CNT-fibers driven
with another type of multiple electrical waveforms in accordance
with the present disclosure.
[0028] FIG. 13 is a front-view of an example of an implementation
of a non-ortho-fabric-material with a plurality of CNT-fibers in
accordance with the present disclosure.
[0029] FIG. 14 is a front-view of an example of an implementation
of a non-ortho-fabric-material with a plurality of CNT-fibers in
accordance with the present disclosure.
[0030] FIG. 15 is a front-view of an example of an implementation
of an ortho-fabric-material with a plurality of CNT-fibers and
plurality of sensors in accordance with the present disclosure.
[0031] FIG. 16 is a top-view of a system block diagram is shown of
an example of an implementation of micro-vibratory sensors and
actuators embedded within the fabric-material or within the
CNT-fibers that combine mechanical action with the electric-field
to enhance dust repelling action of the DMS.
[0032] FIG. 17 is a front-view of the system block diagram shown in
FIG. 16 of the micro-vibratory sensors embedded within the
fabric-material or within the CNT-fibers in accordance with the
present disclosure.
[0033] FIG. 18 is a side-view of a system block diagram of an
example of an implementation of the DSM with a DMS controller and
the micro-vibratory sensors and actuators shown if FIGS. 16 and 17
in accordance with the present disclosure.
[0034] FIG. 19A is a front-view of an example of a first
implementation of a printed flexible conductor and conductive-fiber
pattern for use with the DMS in accordance with the present
disclosure.
[0035] FIG. 19B is a front-view of an example of a second
implementation of a printed flexible conductor and conductive-fiber
pattern for use with the DMS in accordance with the present
disclosure.
[0036] FIG. 19C is a front-view of an example of a third
implementation of a printed flexible conductor and conductive-fiber
pattern for use with the DMS in accordance with the present
disclosure.
[0037] FIG. 20 is a top-view of an example of an implementation of
the DMS utilizing an ortho-fabric-material for a spacesuit and a
plurality of CNT-fibers for the plurality of conductive-fibers in
accordance with the present disclosure.
[0038] FIG. 21 is a top-view of an example of another
implementation of the DMS utilizing the ortho-fabric-material for a
spacesuit and a plurality of CNT-fibers for the plurality of
conductive-fibers in accordance with the present disclosure.
[0039] FIG. 22 is a flowchart illustrating an example of an
implementation of a method of dust mitigation performed by the DMS
in operation in accordance with the present disclosure.
DETAILED DESCRIPTION
[0040] Disclosed is a Dust Mitigation System ("DMS"). The DMS
includes: a fabric-material having a front-surface and a
back-surface; a plurality of conductive-fibers within the
fabric-material; and a plurality of input-nodes approximately
adjacent to the fabric-material. The plurality of conductive-fibers
are approximately parallel in a first direction along the
fabric-material and are approximately adjacent to the front-surface
of the fabric-material and the plurality of input-nodes are in
signal communication with the plurality of conductive-fibers and
configured to receive an alternating-current ("AC") voltage-signal
from an input-signal-source. The plurality of conductive-fibers are
configured to generate an electric-field on the front-surface of
the fabric-material in response to the plurality of input-nodes
receiving the AC voltage-signal from the input-signal-source and a
traveling-wave (of the electric-field) that travels along the
front-surface of the fabric-material in a second direction that is
approximately transverse to the first direction. More specifically,
the phase of AC voltage-signals in the plurality of
conductive-fibers may be adjusted to create the traveling-wave of
the electric-field that travels along the front-surface of the
fabric-material in a second direction that is approximately
transverse to the first direction. By adjusting the phase of the AC
voltage-signal or the slight divergence in the angle of the
approximately parallel conductive-fibers, the approximate
transverse angle of the second direction (i.e., the direction of
the travelling-wave) may be adjusted from a transverse angle (i.e.,
90 degrees) to a non-transverse angle that is still approximately
transverse (i.e., approximately 90 degrees--for example
approximately 80 degrees to approximately 120 degrees).
[0041] In an example of operation, the DMS performs a method that
includes receiving the AC voltage-signal from the
input-signal-source at the plurality of input-nodes, generating the
electric-field on the front-surface of the fabric-material with the
plurality of conductive-fibers, and generating the traveling-wave,
from the electric-field, that travels along the front-surface of
the fabric-material in the second direction that is at the pre-set
angle to the first direction.
[0042] The DMS implements an electrodynamic dust shield ("EDS")
with active electrodes into a spacesuit, or other device or systems
(such as flexible space habitats, deployable structures, etc.) that
utilizes fabric-materials or other flexible-materials by utilizing
conductive-fibers as electrodes. In this example, the active
electrodes are conductive-fibers that may be carbon-nanotube
("CNT") fibers which are flexible electrically conductive-fibers.
Generally, EDS technology utilizes electrostatic and/or
electrodynamic and/or dielectrophoretic forces to repel dust
particles from approaching the surface, and/or carry deposited dust
particles off the surface of a material. Repelling of dust
particles is accomplished by creating electric fields that levitate
the approaching dust particles away from the surface. Deposited
dust particles are carried away by breaking the adhesive forces
between the dust and the surface due to electrostatics or Van der
Waal forces and then levitate the dust away from the surface of the
material. The magnitude of the forces repelling, levitating and
carrying away dust particles depends on the dielectric properties
of the dust particles, the substrate (in this case flexible
structures), the size of the dust particles, and the
characteristics of the input AC voltage-signals applied. As an
example utilizing the DMS, typical electrodynamic forces required
to repel dust particles with sizes between about 10 micrometers
(".mu.m") to 75 .mu.m may be generated by applying AC
voltage-signals in the range of approximately 800 volts ("V") to
1,200V utilizing approximately 180 .mu.m to 200 .mu.m thick
uninsulated CNT fibers spaced between approximately 1.2 millimeters
("mm") to 2.0 mm apart.
[0043] In this example, the DMS includes a fabric-material having a
top-surface where a portion of the top-surface (also herein
referred to as a "shield" having a "shield area" associated with
the portion of the top-surface) includes a series (i.e., a
plurality) of approximately parallel or slightly divergent (for
example with a divergence of approximately 15 to 20 degrees)
conductive-fibers through which an AC voltage-signal of high
voltage (for example, approximately 800V to 1,200V at a frequency
between approximately 5 to 100 Hertz) is applied resulting in the
generation of a traveling-wave of electric-field along the
shield.
[0044] Each conductive-fiber of the plurality of conductive-fibers
may be positioned approximately parallel or slightly divergent to
adjacent conductive-fibers. Additionally, the surface of the fabric
material may be partitioned into different sections, where each
section of the fabric-material may be configured to have different
conductive-fiber patterns that are not parallel to other sections
of the shield. For example, the shield may include sections that
are at angles up to approximately 90 degrees from other sections of
the shield. The position and spacing of the plurality of
conductive-fibers depends upon the application and enables
re-configurability of the traveling-wave of the electric-field
along the shield. In this example, the resulting traveling-wave of
the electric-field repels the dust particles on the shield and the
repelled dust particles travel in a direction that is along or
against the direction of the travelling-wave, depending on the
dielectric properties of the dust particles and the charges (and
induced charges) on the dust particles. This approach also prevents
further accumulation of dust particles on the shield and removes
most charged dust particles from the shield. In general, the
conductive-fibers may either be excited by utilizing single-phase
or multi-phase AC voltage-signals.
[0045] In general, the DMS may be configured to operate in multiple
ways that include, for example, an initial configuration of the DMS
at fabrication and/or a reconfiguration of the DMS after the
activation of the DMS during operation. Specifically, as an
example, when fabricating the DMS on a device (such as, for
example, a spacesuit, space habitat, inflatable structures,
fabric-based antenna, blanket, flexible material devices, or other
similar systems, devices, or components), the orientation of the
conductive-fibers may be designed and configured to allow for
various contours, flexibility, or both of the fabric-material in
which the DMS is implemented so as to optimize the dust repelling
properties of the DMS. Additionally, the type of fabric-material
may be chosen to have electrical and mechanical properties that
optimize the operation of the DMS. As an example, the configuration
of both the placement and geometric alignment of the
conductive-fibers within the fabric-material and the optimization
of the surface properties of the fabric or flexible material are
directly related to the physical robustness and dust repelling
(i.e., dust mitigation) performance of the DMS.
[0046] Additionally, as a reconfiguration during operation example,
the DMS may include feedback controlled electronics (described
later in relation to FIGS. 16 to 18), electromechanical devices, or
both within (or associated with) the fabric-material or
flexible-material that receive inputs from sensors associated with
or within the shield area of either the fabric-material or
flexible-material. Examples of the sensors may include optical or
capacitive sensors that may be located on, or within, the shield
area of the fabric-material or flexible-material or somewhere
remote from the shield area but associated with the fabric-material
or flexible-material shield area. As such, these sensors may be
local sensors within the shield area embedded within the
fabric-material or flexible-material, the conductive-fibers
themselves, or both. Additionally, the sensors may be remote
sensors that are located remote from the shield areas such as, for
example, sensors located at different areas of a spacesuit or other
devices or systems associated with the DMS at the shield area. As a
further example, some of these sensors may be completely remote
from the shield areas such as sensors on a weather satellite (or
satellites) that provide dust data to the DMS for adjusting the
operation of the DMS to better optimize dust mitigation on the
shield.
[0047] In all of these sensor examples, the sensors provide sensor
output signals (which are information signals having sensor data
information that was produced by the individual sensors) to a DMS
controller of the DMS. The DMS controller is configured to vary the
waveforms and frequencies of the AC voltage-signals provided to the
conductive-fibers based on the received sensor output signals so as
to optimize the dust mitigation properties of the DMS. The DMS
controller may be in signal communication with the
input-signal-source and capable of fixing or adjusting the
individual AC voltage-signals produced by the input-signal-source
in voltage, frequency, and phase in response to the received sensor
output signals. In this example, the DMS controller may be any
general electronic controller that may include a microcontroller, a
central processing unit ("CPU") based processor, digital signal
processor ("DSP"), an application specific integrated circuit
("ASIC"), field-programmable gate array ("FPGA"), or other similar
device or system.
[0048] In addition to sensors, the DMS may also include a plurality
of actuators that may be located on the back-surface of the
fabric-material or flexible material below the shield area. These
actuators may be electromechanical devices capable of moving,
shaking, vibrating, or performing other types of mechanical work
that assists in dislodging, moving, and repelling dust particles on
the shield. The actuators are in signal communication with the DMS
controller and the DMS controller is also configured to control the
operation of the actuators based on the received sensor output
signals so as to optimize the dust mitigation properties of the DMS
at the shield. Utilizing the sensors, actuators, or both, the DMS
controller is configured to adjust the AC voltage-signals from
input-signal-source to optimize the dust mitigation of the DMS
based on the properties of the fabric-material or flexible-material
(e.g., the layers, coatings, dielectric properties, etc.) and the
dust (e.g., the size, mass, dielectric proprieties, distribution,
etc.). As such, the DMS controller is configured to vary the AC
voltage-signals to adjust the mode of operation of the DMS.
[0049] As an example in a first mode of operation (i.e., a dynamic
dust movement mode), a first optimized AC voltage-signal having a
first waveform and first frequency value may be utilized by the DMS
to repel dust before the dust settles on the shield of the
fabric-material. Alternatively, as an example of a second mode of
operation where static dust has settled (i.e., shield is
predisposed to dust prior to activation of DMS) on the shield of
the fabric-material, a second optimized AC voltage-signal having a
second waveform and second frequency value may be utilized by the
DMS to repel dust that has settled on the shield of
fabric-material.
[0050] For example, if the DMS is active prior to the dust settling
on the shield, about 90 percent or more of the dust is repelled
utilizing a lower voltage AC voltage-signal (e.g., approximately
800V to 900V), while alternatively if the dust has already settled
on the shield prior to activating the DMS, the DMS will need to
utilize a higher voltage AC voltage-signal (e.g., approximately
1,000V to 1,200V) to repel the dust from the shield. Additionally,
once the dust has settled on the shield, the DMS may need to
utilize AC voltage-signals with higher spectral bandwidths that may
be up to approximately 200 Hz to dislodge the settled dust from the
shield. In these examples, the DMS controller may utilize a lookup
database on a storage unit (i.e., a memory unit or module) to
determine the type of AC voltage-signal (i.e., the type of signal
waveform, frequency, voltage, phase, etc.) to utilize or adjust in
the DMS to dislodge, repel, or both, the dust that is settling or
settled on the shield based on input data from sensors that may
provide the status of dust contamination on the shield. The lookup
database may include values based on the sensors or other sources
that are in signal communication with the DMS. The storage unit may
be part of the DMS or remote but in signal communication with the
DMS. As an example, the location of the driving and control
electronics that generate the AC voltage-signals (such as, for
example, the input-signal source) that are passed to the
conductive-fibers within the fabric-material may be locally
embedded in the fabric-material, centrally located and/or remote
from the DMS, or co-located with the DMS and the rest of the device
that the DMS is implemented on such as, for example, the systems
and electronics of a spacesuit.
[0051] In FIG. 3A, a side-view of a system block diagram is shown
of an example of an implementation of a DMS 300 in accordance with
the present disclosure. The DMS 300 includes a fabric-material 302
having a front-surface 304 and back-surface 306, a plurality of
conductive-fibers 308 within the fabric-material 302, and a
plurality of input-nodes 310 on the back-surface 306 of the
fabric-material 302 in signal communication with the plurality of
conductive-fibers 308 via a first plurality of signal paths 312
within the fabric-material 302.
[0052] The plurality of conductive-fibers 308 are configured as a
series (i.e., a plurality) of approximately parallel
conductive-fibers 308 along the fabric-material 302 approximately
adjacent to (i.e., either on or close to) the front-surface 304 and
the plurality of input-nodes 310 are configured as a series of
input-nodes that are approximately adjacent to the back-surface 306
of the fabric-material 302 where each input-node from the plurality
of input-nodes is in signal communication with a corresponding
conductive-fiber from the plurality of conductive-fibers 308 via an
corresponding signal path of the first plurality of signal paths
312. The plurality of conductive-fibers 308 are located within a
shield area 311 that is a portion of the front-surface 304 (also
referred to as the top-surface of the fabric-material 302) defining
the shield 313 of the DMS 300.
[0053] In this example, the plurality of conductive-fibers 308 are
shown as approximately parallel and oriented in first direction 314
along the shield 313 of the fabric-material 302 (within the shield
area 311) that is either into or out of the page in the side-view
of FIG. 3A. For the purposes of illustration, the first direction
314 is shown as being into the page, however, it is appreciated by
those of ordinary skill in the art that the first direction 314 may
alternatively be in the opposite direction out of the page without
limiting the present disclosure. If the plurality of
conductive-fibers 308 are not parallel, the plurality of
conductive-fibers 308 may be slightly divergent such as, for
example, the plurality of conductive-fibers 308 may be divergent
with approximately 15 to 20 degrees of deviation from parallel.
[0054] In this example, the plurality of conductive-fibers 308 are
woven, or braided, into the front-surface 304 of the
fabric-material 302 (where the fabric-material 302 may be, for
example, a woven (or braided) fabric-material, flexible-material,
or both) at the shield 313. Additionally, each conductive-fiber of
the plurality of conductive-fibers 308 may be a carbon-nanotube
("CNT") fiber. Moreover, each input-node of the plurality of
input-nodes 310 may be an electrode. Furthermore, each
conductive-fiber of the plurality of conductive-fibers 308 may also
be an electrode.
[0055] In this example, the plurality of conductive-fibers 308 are
configured to receive an AC voltage-signal 316 from an
input-signal-source 318 (via a second plurality of signal paths
320, the plurality of input-nodes 310, and the first plurality of
signal paths 312), where the input-signal-source 318 is in signal
communication with the plurality of input-nodes 310 via the second
plurality of signal paths 320. In an example of operation, once the
plurality of conductive-fibers 308 receive the AC voltage-signal
316, each conductive-fiber of the plurality of conductive-fibers
308 is electrically energized and acts as an electrical
radiating-element along (or approximately adjacent to) the
front-surface 304 of the fabric-material 302 resulting in an
electric-field 322 along the front-surface 304 of the
fabric-material 302. The electric-field 322 generates a
traveling-wave along the front-surface 304 of the fabric-material
302 in a second direction 324 that is transverse to the first
direction 314. It is appreciated that the second direction 324 may
optionally be from left-to-right or from right-to-left based on the
characteristics of the electric-field 322 or at a preset angle to
the traverse.
[0056] In this example, the input-signal-source 318 may be a
three-phase power supply signal-source that produces the AC
voltage-signal 316 as a three-phase AC voltage-signal 316 having a
plurality of AC phased-signals that include a first-phase signal
326, second-phase signal 328, and third-phase signal 330. It is
appreciated by those of ordinary skill in the art that instead of
the input-signal-source 318 being a three-phase input-signal-source
318 producing a three-phase AC voltage-signal 316, other
multi-phase input-signal-sources may be utilized such, for example,
a two-phase or four phase input-signal-source producing a two-phase
or four phase AC voltage-signal respectively may also be utilized.
Once the AC voltage three-phase signals 326, 328, and 330 are
applied to the DMS 300, any dust particles 332 on the front-surface
304 of the fabric-material 302 are repelled and moved off the
front-surface 304 for the fabric-material 302 in a repulsion
direction 334 that is parallel to the first direction 314. Turning
to FIG. 3B, a top-view of a system block diagram is shown of the
implementation of the DMS 300 (shown in FIG. 3A) in accordance with
the present disclosure.
[0057] It is noted that while the plurality of input-nodes 310 are
shown approximately adjacent to the back-surface 306, this is for
the purpose of illustration because the plurality of input-nodes
310 may be located in varying positions adjacent to the
fabric-material 302. As an example, the plurality of input-nodes
310 may be located on the back-surface, within the fabric-material
302 adjacent but just below the back-surface 306, on the
front-surface 304, within the fabric-material 302 adjacent but just
below the below the front-surface 304, at a side (not shown) of the
fabric-material, within the fabric-material with an access via to
either the front-surface 304 or back-surface 306, or any place
adjacent the fabric-material that does not result in unacceptable
interference with the generated electric-field 322 when the
plurality of conductive-fibers 308 are feed with the AC
voltage-signal 316, since the AC voltage-signal 316 will induce an
electromagnetic fields from the plurality of input nodes 310 and
the first plurality of signal paths 312 that if too close to the
plurality of conductive-fibers 308 may interact and/or interfere
with the induced currents produced by the AC voltage-signal 316 on
the plurality of conductive-fibers 308 and/or the resulting
electric-field 322.
[0058] The circuits, components, modules, and/or devices of, or
associated with, the DMS 300 are described as being in signal
communication with each other, where signal communication refers to
any type of communication and/or connection between the circuits,
components, modules, and/or devices that allows a circuit,
component, module, and/or device to pass and/or receive signals
and/or information from another circuit, component, module, and/or
device. The communication and/or connection may be along any signal
path between the circuits, components, modules, and/or devices that
allows signals and/or information to pass from one circuit,
component, module, and/or device to another and includes wireless
or wired signal paths. The signal paths may be physical, such as,
for example, conductive wires, electromagnetic wave guides, cables,
attached and/or electromagnetic or mechanically coupled terminals,
semi-conductive or dielectric materials or devices, or other
similar physical connections or couplings. Additionally, signal
paths may be non-physical such as free-space (in the case of
electromagnetic propagation) or information paths through digital
components where communication information is passed from one
circuit, component, module, and/or device to another in varying
digital formats without passing through a direct electromagnetic
connection.
[0059] In this example, the plurality of conductive-fibers 308 are
a plurality of CNT-fibers that are utilized as electrodes within
the fabric-material 302 because they are good electrical conductors
and are mechanically strong and flexible (i.e., they have high
resilience to fatigue) when compared to traditional metal
electrodes. It is appreciated by those of ordinary skill in the art
that CNT-fibers are a high performance technology breakthrough
material with applications in nanotechnology, electronics, material
science, optics, etc. Generally, CNT-fibers are multifunctional
materials that combine the best properties of polymers, carbon
fibers, and metals because CNT-fibers have exceptional properties
of mechanical strength and stiffness, electrical and thermal
conductivity, and low density (e.g., approximately 1 g/cm.sup.3 for
a CNT-fiber compared to about 8.96 g/cm.sup.3 for copper) that
exist on the molecular level. Specifically, CNT-fibers are
allotropes of carbon with a cylindrical nanostructure that have a
cylindrical structure with a diameter of about one nanometer ("nm"
equal to 10.sup.-9), a length-to-diameter ratio up to about
132,000,000 to 1, high thermal conductivity (with a range of
approximately 100 mWm.sup.2/kgK to 1000 mWm.sup.2/kgK), normalized
electrical conductivity (with a range of approximately 1 kS
m.sup.2/kg to 6 kS m.sup.2/kg, normalized by density), and high
mechanical strength and stiffness (with a tensile strength in the
approximate range of 1 GPa to 1.3 GPa).
[0060] At present, lightweight CNT-fibers may be produced with
lengths that are on the orders of meters while having properties
approaching the high specific strength of polymeric and
carbon-fibers, high specific electrical conductivity of metals, and
specific thermal conductivity of graphite-fibers as shown recently
by academic sources. These CNT-fibers are high-strength fibers with
relatively low-conductivity (e.g., about 1.1 MS/m for a CNT-fiber)
when compared to high-conductivity metals (e.g., about 49 MS/m for
off the shelf copper magnet wire) that have relatively low-strength
such as, for example, copper. However, while the electrical
conductivity for these CNT-fibers might be lower than copper and
other known highly conductive materials, the advantage of
CNT-fibers is their low-density that makes the current carrying
capacity ("CCC"), when normalized by mass, much higher than the
metal conductors.
[0061] As a result of these properties, in the present example,
CNT-fibers have been utilized as the plurality of conductive-fibers
308 of the DMS 300 because the CNT-fibers overcome the challenges
of integrating the DMS 300 with metal wires or strips as electrodes
instead of the conductive-fibers 308. Specifically, the mechanical
properties of CNT-fibers are higher than the mechanical properties
of the high-conducting metallic-materials and the mass of a
CNT-fiber is low compared to a metal electrode. Therefore, even if
the CNT-fiber thickness needs to be increased to match the
low-resistance of a metal electrode, the overall mass contribution
of the CNT-fiber is less than that of the metal electrode. It is
appreciated that while the CNT-fibers are utilized in this example,
other fibers such as Litewire may be also utilized, in other
applications, as long as the other fibers have high-strength with
high-resilience to fatigue, high-conductivity on par with
metallic-materials, and that the mass of the other fibers are low
when compared to metal-electrodes.
[0062] As such, the utilization of CNT-fibers for the plurality of
conductive-fibers 308 within the fabric-material 302 are preferred
because the fabric-material 302 is flexible and in the case of
spacesuit fabrics, flexible and complex to fabricate. Specifically,
the use of metallic-materials (such as, for example, copper or
indium tin oxide) within the fabric-material 302 of a spacesuit
would be difficult because the metallic-materials are challenged by
fatigue breakage and often exhibit high cycle fatigue resulting in
failure of the metallic-materials due to cyclic loading under
repeated loads. Unfortunately, spacesuits, as an example, undergo
repeated motions that flex, bend, fold, or twist spacesuit
materials (e.g., fabric-materials and other such
flexible-materials) specifically within the leg or arm portions of
the spacesuit. As such, spacesuit-materials need to be highly
flexible and nearly fatigue-free. Additionally, fabricating a
spacesuit with these metallic-materials is also challenging because
the spacesuits have irregular contours and non-smooth surfaces. As
a result, with spacesuit fabric-materials, it is not possible to
adhere metallic-material wires to the fabric-material surfaces of a
spacesuit utilizing known techniques such as, for example,
sputtering or ink-jet printing. Additionally, spacesuit
fabric-materials (e.g., beta cloth, ortho-fabric, or both, or other
examples of suitable fabric-materials or flexible-materials, such
as used in BIOSUIT.RTM. or flexible materials used for space
habitats, inflatable structures, flexible deployable antennas and
combinations thereof) that are exposed to dust are generally coated
with polytetraflouroethylene ("PTFE" a synthetic fluoropolymer of
tetrafluorethylene generally known as "TEFLON.RTM.") that is not
conducive to directly bonding any electrodes to the surface of
spacesuit materials. However, it is noted that for other
fabric-materials in which bonding is suitable, the electrodes may
be bonded without departing from the spirit of the present
disclosure.
[0063] It is appreciated that beta-cloth is a type of fireproof
silica fiber cloth used in the manufacture of spacesuits such as
the Apollo/Skylab A7L spacesuits and the Apollo thermal
micrometeroid garment. In general, beta-cloth includes fine woven
silica fiber that is similar to fiberglass and is a fabric-material
that is coated with PTFE and will not burn and will only melt at
temperatures exceeding 650.degree. C. Ortho-fabric is utilized for
the outer layer of the spacesuit and includes a complex weave blend
of GORE-TEX.RTM. (i.e., a synthetic waterproof fabric-material that
includes a membrane that is permeable to air and water vapor),
KEVLAR.RTM. (i.e., poly-paraphenylene terephthalamide, a
para-aramid synthetic fiber of high tensile strength), and
NOMEX.RTM. (a flame-resistant meta-aramid synthetic fiber)
materials.
[0064] Turning to FIG. 4, a top-view of an implementation of a
weave 400 of the fabric-material 302 with the plurality of
conductive-fibers 308 (shown in FIGS. 3A and 3B) is shown in
accordance with the present disclosure. Similar to the examples
shown in FIGS. 3A and 3B, seven (7) conductive-fibers 308 are shown
within the shield area 311 of the fabric-material 302, however, it
is appreciated by of ordinary skill in the art that any plurality
of conductive-fibers 308 may be utilized based on the desired
repulsive properties of the shield 313.
[0065] In this example, the conductive-fibers 308 are CNT-fibers
that are weaved into the fabric-material 302. Moreover in this
example, the weave 400 of the fabric-material 302 is shown having a
plurality of fabric-material 302 warp threads 402 (i.e., a
plurality of fabric-material 302 horizontal threads) and plurality
of fabric-material 302 welt threads 404 (i.e., a plurality of
fabric-material 302 vertical threads) forming the front-surface 304
of the fabric-material 302 and a plurality of insulating threads
406 adjacent to and in-between the plurality of conductive-fibers
308. In this example, the plurality of fabric-material 302 warp
threads 402, plurality of insulating threads 406, and plurality of
conductive-fibers 308 run along the first direction 314 of the
weave 400 while the plurality of fabric-material 302 welt threads
404 run along the second direction 324 of the weave 400. In this
example, the fabric-material 302 may be an ortho-fabric-material
and the plurality of fabric-material 302 warp threads 402 and
plurality of fabric-material 302 welt threads 404 are threads
(i.e., a yarn or textile fibers) of the ortho-fabric-material
generally two-plied (i.e., two threads of material twisted together
("plied") to for a "2-ply" thread) or multi-ply (i.e., more than
2-ply) textile fibers utilized to produce the weave 400 of
fabric-material 302. It is appreciated by those of ordinary skill
in the art that the fabric material 302 is generally at least
2-plyed to increase the strength of the fabric-material 302.
Additionally, the plurality of insulating threads 406 may also be
of the same ortho-fabric-material as the plurality of
fabric-material 302 warp threads 402 and plurality of
fabric-material 302 welt threads 404 as long as the
ortho-fabric-material is capable of electrically insulating each
conductive-fiber of the plurality of conductive-fibers 308 from
each other. Furthermore, each conductive-fiber of the plurality of
conductive-fibers 308 may also be 2-plyed or multi-plied
conductive-fibers. As such, in this example, the fabric-material
302 is shown as a sub-weave 408 of the weave 400 of the
fabric-material 302. The sub-weave 408 includes the plurality of
conductive-fibers 308 (as a plurality of warp conductive-fibers)
along the plurality of fabric-material 302 welt threads 404 and in
between the plurality of fabric-material 302 warp threads 402,
where the sub-weave 408 includes the plurality of insulating
threads 406 spaced in-between the plurality of conductive-fibers
308.
[0066] In this example the plurality of conductive-fibers 308 and
plurality of insulating threads 406 are shown as extending
uniformly in one direction (i.e., first direction 314), however, it
is noted that the plurality of conductive-fibers 308 and plurality
of insulating threads 406 may be intermixed in both warp and weft
in any ordering or pattern desired based on the design of the DMS
300 as will be shown later in this disclosure. It is further noted
that the plurality of insulating threads 406 may have a dielectric
constant value or values that do not significantly diminish the
traveling-wave of the electric-field 322 produced by the DMS 300.
While the weave 400 of fabric-material 302 is shown in this
example, it is noted that the fabric-material 302 may instead be
braided.
[0067] Turning to FIGS. 5A, 5B, and 5C, front and back view is
shown of an example of an implementation of a weave, or braid, of
the fabric-material 302 as an ortho-fabric-material 500 (e.g., the
outer-layer material of the spacesuit) with a plurality of
CNT-fibers 502 utilized as the plurality of conductive-fibers 308
in accordance with the present disclosure. In FIGS. 5A and 5B, the
front-surface 304 (also referred to herein as the "top-side") of
the ortho-fabric-material 500 is shown while in FIG. 5C, the
back-surface 306 of the ortho-fabric-material 500 is shown. FIG. 5A
is an amplified front-view of the front-surface 304 of the
ortho-fabric-material 500 showing a single CNT-fiber 504 (of the
plurality of CNT-fibers 502) woven, or braided, into the threads
(i.e., fibers) of the ortho-fabric-material 500, while FIG. 5B
shows a less amplified front-view of the front-surface 304 of the
ortho-fabric-material 500 showing multiple CNT-fibers (of the
plurality of CNT-fibers 502) woven, or braided, into the threads of
the ortho-fabric-material 500. In this example, the plurality of
CNT-fibers 502 do not penetrate the entire fabric-material 302
thickness of the ortho-fabric-material 500. The weave, or braid, is
done such that only the front-surface 304 has the plurality of
CNT-fibers 502. As such, in FIG. 5C, the ortho-fabric-material 500
is shown not to have any CNT-fibers 502 passing through the
back-surface 306 of the ortho-fabric-material 500.
[0068] In FIG. 6, an angled side-view of an example of an
implementation of a portion of two CNT-fibers 600 and 602 is shown
in accordance with the present disclosure. The two CNT-fibers 600
and 602 (of the plurality of CNT-fibers 502, FIGS. 5A-5C) may
include side fibrils 604 and 606 (i.e., generally known as "hairs"
of the CNT-fiber) that are formed by slightly frayed strands in the
CNT-fibers 600 and 602, which may be oriented in an organized or
random fashion. In generally, the utilization of the side-fibrils
604 and 606 increases the dust repellant effect of the DMS 300 by
creating irregularities in the electric-field 322, FIG. 3A.
[0069] In FIGS. 7A, 7B, and 7C, front-views of an example of an
implementation of the insulation of the plurality of CNT-fibers 502
(shown in FIGS. 5A, 5B, and 5C) on the front-surface 304 of the
ortho-fabric-material 500 are shown in accordance with the present
disclosure. In this example, a plurality of thermoplastic-fibers
700 are mounted during the fabrication of the ortho-fabric-material
500. In this example, the assembled ortho-fabric-material 500 and
the plurality of thermoplastic-fibers 700 are annealed at elevated
temperatures, melting the thermoplastic-fibers 700 to create a
micron-sized insulating layer 702 that increase the safety of the
combination of ortho-fabric-material 500 and the plurality of
CNT-fibers 502 while only having minimal reduction in the
electric-field 322 (for example, less than approximately 10%
reduction) that repeals the dust particles 332. In FIG. 7C, a
top-layer coating 704 is shown completely covering the
front-surface 304 of the ortho-fabric-material 500 and plurality of
CNT-fibers 502. The top-layer coating 704 may be electrically
insulating or polarizing for local enhancement of the
electric-field 322. The top-layer coating 704 may be applied after
the assembly of the plurality of CNT-fibers 502 and the
front-surface 304 of the ortho-fabric-material 500 is complete. As
an example, the top-layer coating 704 may be hydrophobic-material
with patterning of the surface texture for maximum hydrophobicity
(such as, for example, Lotus coating developed by NASA GSFC) and/or
a material that bends the electronic-bands structure of the
assembly (i.e., the coating plus CNT-fibers) to equalize the
bandgap of the plurality of CNT-fiber 502 in the shield 313 to the
typical bandgap of dust particles (as an example, the work-function
developed at NASA GRC).
[0070] Turning to FIG. 8, an amplified front-view of an example of
another implementation of an ortho-fabric-material 800 with a first
plurality of CNT-fibers 802 and second plurality of CNT-fibers 804
is shown in accordance with the present disclosure. In this
example, the first plurality of CNT-fibers 802 and second plurality
of CNT-fibers 804 are shown to have multi-directional patterning.
As an example, two areas 806 and 808 of the ortho-fabric-material
800 are shown with the first area 806 having the first plurality of
CNT-fibers 802 oriented in a "vertical" direction (i.e., a vertical
weave) while the second area 808 having the second plurality of
CNT-fibers 804 oriented in a "horizontal" direction (i.e.,
horizontal weave).
[0071] Similarly, in FIG. 9, a front-view of an example of yet
another implementation of an ortho-fabric-material 900 with a first
plurality of CNT-fibers 902 and second plurality of CNT-fibers 904
is shown in accordance with the present disclosure. In this
example, the first plurality of CNT-fibers 902 and second plurality
of CNT-fibers 904 are superimposed in a "vertical" weave and
"horizontal" weave, insulated by a thin film of insulating-material
or fabric-material. The superimposed weaves may be variable and/or
different to enhance the electric-field 322. The individual
CNT-fibers of the first plurality of CNT-fibers 902 and second
plurality of CNT-fibers 904 may be insulated on either side of the
individual CNT-fibers.
[0072] In FIG. 10, a front-view of an example of still another
implementation of an ortho-fabric-material 1000 with a first
plurality of CNT-fibers 1002 and second plurality of CNT-fibers
1004 is shown in accordance with the present disclosure. In this
example, the first plurality of CNT-fibers 1002 and second
plurality of CNT-fibers 1004 may have varying spacing and
dimensions. The width (e.g., diameter) of the individual CNT-fibers
of the first and second plurality of CNT-fibers 1002 and 1004 are
not restricted to 90 degrees. The distance between the individual
adjacent CNT-fibers of the first and second plurality of CNT-fibers
1002 and 1004 may vary. Additionally, the clustering of the first
and second plurality of CNT-fibers 1002 and 1004 may vary with
inter-fiber distances having a wider spacing 1006 and a narrow
spacing 1008.
[0073] In FIG. 11, a front-view of an example of an implementation
of an ortho-fabric-material 1100 with a plurality of CNT-fibers
1102 driven with multiple electrical waveforms is shown in
accordance with the present disclosure. In this example, the
plurality of CNT-fibers 1102 are driven by a low-frequency (for
example 10 Hz) AC, multi-phase sinusoidal signal 1104 with
three-phases among six CNT-fibers (phase-one 1106, phase-two 1108,
and phase-three 1110). Similarly, in FIG. 12, a front-view is shown
of an example of an implementation of the ortho-fabric-material
1100 with the plurality of CNT-fibers 1102 driven with another type
of multiple electrical waveforms in accordance with the present
disclosure. In this example, the plurality of CNT-fibers 1102 are
driven by a low-frequency (for example 10 Hz) AC, multi-phase
sinusoidal signal 1200 with two-phases among four CNT-fibers
(phase-one 1202 and phase-two 1204). These examples allow for
wider-spectrum waveforms with random spectral components (in the
range of 0.1 Hz to 100 Hz) distributed among clusters of CNT-fibers
1102.
[0074] In FIG. 13, a front-view of an example of an implementation
of a non-ortho-fabric-material 1300 with a plurality of CNT-fibers
1302 is shown in accordance with the present disclosure.
[0075] In FIG. 14, a front-view of an example of an implementation
of a non-ortho-fabric-material 1400 with a plurality of CNT-fibers
1402 and 1404 is shown in accordance with the present disclosure.
The non-ortho-fabric-materials 1300 and 1400 may be substrates with
ribbons having flexible fibers, oriented fibers of non-conductive
material (as example non-conductive polymer), which has the
CNT-fibers 1302, 1402, and 1404 embedded at predetermined intervals
in a matrix. The ribbons may be stabilized with a backing made of
matrix curing material. The non-ortho-fabric-materials 1300 and
1400 may alternatively be charged fabric fibers utilizing charged
polymers that allow local enhancement of the electric-field 322 for
complex geometric contours of the assembly. The
non-ortho-fabric-materials 1300 and 1400 may also be conductive
polymers with embedded CNT-fibers where the fabric-material is
composed of two different types of fibers such as one strand of
2-ply that is conductive and one strand that is insulative. In
general, materials used in the 1-ply strands and in the first
(i.e., non-conductive) side of the two-ply strands should have a
dielectric constant that does not significantly diminish the
traveling-wave of the electric-field 322 presented in the first
(i.e., nonconductive) side of the fabric-material. Additionally,
the spacing, ordering, and pattern of non-conductive and conductive
strands and the phasing and frequency of the input-signal-source
318 may be designed to tailor repelling and dispersing effects on
the first (non-conductive) surface of the fabric-material. For
example, to repel dust particle sizes between approximately 5 to
300 .mu.m in lunar conditions, the ranges for conductive-fiber
width are anticipated to be between approximately 0.5 to 400 .mu.m,
conductive-fiber spacing between approximately 0.3 to 4 mm,
voltages between approximately 500 to 2,000V, frequency between
approximately 5 to 200 Hz, and single to multiphase input signals.
These parametric values may increase by a factor of approximately 3
to 5 for Earth applications to account for the effects of gravity,
humidity and atmospheric conditions.
[0076] Turning to FIG. 15, in FIG. 15 an amplified front-view of an
example of an implementation of an ortho-fabric-material 1500 with
a plurality of CNT-fibers 1502 and plurality of sensors 1504 is
shown in accordance with the present disclosure. The sensors 1504
may be micro-sensors that are attached to the ortho-fabric-material
1500 or embedded within the plurality of CNT-fibers 1502. The
sensors 1504 are configured to identify the amount of dust coverage
that may then activate the DMS 300 with the AC voltage-signal 316
based on the pre-specified minimum dust coverage value. The sensors
1504 may sense the optical reflectively on the front-surface 1506
of the ortho-fabric-material 1500, change in mass, etc.
[0077] In FIG. 16, a top-view of a system block diagram is shown of
an example of an implementation of micro-vibratory sensors and
actuators 1600 embedded within the fabric-material 1602 or within
the CNT-fibers 1604 (that are woven into the fabric-material 1602)
that combine mechanical action with the electric-field 322 to
enhance dust repelling action of the shield 313 of the DMS 300.
[0078] In FIG. 17, a front-view (along plane A-A 1606) is shown of
the system block diagram shown in FIG. 16 of the micro-vibratory
sensors and actuators 1600 embedded within the fabric-material 1602
or within the plurality of CNT-fibers 1604 in accordance with the
present disclosure. The plurality of CNT-fibers 1604 (i.e., a
series of approximately parallel CNT-fibers) are woven into the
fabric-material 1602 which, in this example, may be the
ortho-fabric-materials of a spacesuit. The fabric-material 1602 has
an outermost layer 1700 and on top of the outermost-layer 1700 is a
work-function coating 1702. The fabric-material 1602 also includes
an underneath-layer 1704 of the fabric-material 1602 underneath the
outermost-layer 1700. The micro-vibratory sensors and sensors 1600
are located between the outermost-layer 1700 and underneath-layer
1704. In this example, the DMS 300 combines a passive,
electrostatic, and vibratory mechanical action to repel dust off of
the shield 313.
[0079] Turning to FIG. 18, a side-view is shown of a system block
diagram of an example of an implementation of the DMS 1800 with a
DMS controller 1801 and the micro-vibratory sensors and actuators
1600 (shown in FIGS. 16 and 17) in accordance with the present
disclosure. This example is similar to the example shown in FIG. 3A
with the added elements of a first sensor 1802, a second sensor
1804, and an actuator 1806 within the micro-vibratory sensors and
actuators 1600, and the DMS controller 1801. In this example, as
described earlier, the DMS controller 1801 may be any general
electronic controller that may include a microcontroller, a CPU
based processor, DSP, an ASIC, FPGA, or other similar device or
system. The first sensor 1802 and second sensor 1804 are devices
capable of identifying the amount of dust particle 332 coverage on
the shield 313 and then provide that information to the DMS
controller 1801, which is in signal communication with the first
and second sensors 1802 and 1804 via signal paths 1808 and 1810,
respectively. The first and second sensors 1802 and 1804 may be
micro-sensors that are powered by a DMS power supply (not shown) or
by harvesting the mechanical energy from the motion of the wearer
of the DMS 1800. The first and second sensors 1802 and 1804
determine the amount of dust particle 332 coverage on the shield
313 and provide that information to the DMS controller 1801 via
sensor data signals 1812 and 1814 that are transmitted to the DMS
controller 1801 via the signal paths 1808 and 1810, respectively.
Once received by the DMS controller 1801, the DMS controller 1801
then determines if the AC voltage-signal 316 needs to be adjusted
to change the characteristics of the electric-field 322 on the
shield 313 to remove the dust particle 332 on the shield 313. If
the AC voltage-signal 316 needs to be adjusted, the DMS controller
1801 sends an adjustment signal 1816 to the input-signal-source 318
via signal path 1818. Once received, the input-signal-source 318
modifies the waveform and/or frequency of the AC voltage-signal 316
(in response to the adjustment signal 1816) provided to the
plurality of conductive-fibers 308 to optimize the dust mitigation
properties of the DMS 1800. In addition, the DMS controller 1801
may provide an actuation/adjustment signal 1820 to the actuator
1806 via signal path 1822. Once received, the actuator 1806 will
begin to provide mechanical work (e.g., vibrational energy) to the
outermost-layer 1700 of the fabric-material 1602 to assist in
dislodging and/or removing the dust particles 332 from the shield
313. In this example, the actuator 1806 may be a piezoelectric
device (such as, for example, a micro-vibratory device) or some
strands (not shown) within some of the conductive-fibers 308. The
actuator 1806 may operate under the control of the DMS controller
1801, from inputs from the first and second sensors 1802 and 1804,
or other control devices external to the DMS 1800. Similar to the
first and second sensors 1802 and 1804, the actuator 1806 may be
powered by the DMS power supply (not shown) or by harvesting the
mechanical energy from the motion of the wearer of the DMS
1800.
[0080] In this example it is noted that only two sensors 1802 and
1804 and one actuator 1806 are shown for convenience in the
illustration of FIG. 18. It is appreciated, that this is not a
limitation and the DMS 1800 may include a plurality of sensors and
a plurality of actuators below the outermost-layer 1700 of the
fabric-material 1602 without limitation.
[0081] Another application for the DMS 1800 utilizing one or more
actuators is the ability to remove sacrificial coatings (e.g.,
temporary or peel able solar-fabric, camouflage-fabric, coating
needed for optical properties, water repellant, anti-radar, etc.)
by producing high-frequency vibration or low-frequency curving with
the plurality of actuators so assist to peel off of any sacrificial
coatings from the front-surface of the fabric-material 1602.
[0082] In addition to sensors and actuators, the DMS 1800 may also
include one or more micro-heaters (not shown) that are utilized to
assist in the dust mitigation process or personal heating. The
micro-heaters may be utilized to increase the resistivity of the
plurality of conductive-fibers 308 or to provide heat to wearer of
the DMS 1800 via heating the plurality of conductive-fibers 308. In
the example of CNT-fibers for the plurality of conductive-fibers
308, the micro-heaters may be implemented as part of the plurality
of conductive-fibers 308 that may be implemented either on the
outermost-layer 1700 of the fabric-material 1602 or as a secondary
plurality of conductive-fibers (not shown) in the underneath-layer
1704 of the fabric-material 1602. The micro-heaters are configured
to produce a temperature on, or in, the fabric-material 1602 that
may be controlled by the DMS controller 1801 or by direct inputs
from the sensors within the fabric-material 1602. The micro-heaters
may be powered by the DMS power supply.
[0083] It is further noted that the plurality of conductive-fibers
308 may also be utilized for radiation protection of the DMS 1800.
In this example, the weave patterns of the plurality of
conductive-fibers 308 is optimized and the input-signal-source 318
produces AC voltage-signals 316 that generate an electric-field
that repels electrons, protons, or both. This application will
utilize higher frequencies than the dust repellent application of
the DMS 1800 and may be superimposed on the plurality of
conductive-fibers 308 to produce multiple types of waveforms with
wider spectral range in a dual-use implementation. As an example,
the patterns of the conductive-fibers may be varied to create
different zones of spatial patterns of the conductive-fibers where
the spatial separation of the conductive-fibers vary from
zone-to-zone and the spatial separation of the applied waveforms of
the AC voltage-signals vary from zone-to-zone.
[0084] Moreover, the plurality of conductive-fibers 308 may also be
utilized for energy harvesting where the DMS 1800 may be
incorporated in the fabric-materials of spacesuits, mountaineering
clothing and equipment, and government and military suits and
devices. In general, the plurality of conductive-fibers 308 may be
tuned to operate in the frequencies for dust mitigation and a
second frequency (or frequencies) for receiving ambient
electromagnetic energy that may be rectified into harvested into
received electrical power. In addition, in the case of CNT-fibers
for the conductive-fibers, piezoelectric elements may be embedded
within the CNT-fibers or the fabric-material to harvest mechanical
energy from the movement of the wearer and transform it into
electrical power. Furthermore, the CNT-fibers may be configured to
receive ambient thermal energy (e.g., external heat-energy,
radiation from the Sun, heat from the body of the wearer) which is
converted to electrical power via the CNT-fibers acting as
thermoelectric converters.
[0085] Moreover, the plurality of conductive-fibers 308 may also be
utilized for anti-jamming applications in wearable communication
systems or systems utilizing fabric-materials such as, for example,
an antenna utilizing a fabric-material. In this case, the
fabric-material and plurality of conductive-fibers may utilized in
combination with a fabric based antenna system that may be part of
a wearable communication system by utilizing CNT-fibers for the
conductive-fibers. In this example, the CNT-fibers may operate as
sensors capable of detecting a jamming signal or the DMS 1800 may
also include embedded electric-field sensors capable of detecting
the jamming signal. Once a jamming signal is detected, the DMS 1800
may include additional devices, components, or systems capable of
producing an anti-jamming AC voltage-signal with a higher frequency
than the frequencies produced by the DMS 1800 to mitigate the dust
from the shield. In order to produce these anti-jamming AC
voltage-signals, the DMS controller 1801 may be in signal
communication with an external communication system.
[0086] Turning to FIGS. 19A, 19B, and 19C, front-views of examples
of different implementations of printed flexible conductor and/or
conductive-fiber patterns are shown for use with the DMS 300 in
accordance with the present disclosure. The patterns may be placed
on the fabric-material and in signal communication with an active
controller (i.e., the DMS controller) to better control dust
repelling action. The various shapes provide varying optimizing
dust repelling actions. The printed patterns may be then attached
to a flexible-material, fabric-material, and/or surface of the
appropriate dielectric properties.
[0087] It is appreciated by those of ordinary skill in the art that
while most of the examples in this disclosure have been directed to
spacesuits, the disclosure also applies to other types of devices
that utilizes flexible-material or fabric-material such as electric
fences, dust protection systems for wearable communication,
radiation protection, thermal protection, umbrella antennas, tents,
canopy surfaces, flexible solar collectors, flexible solar cells,
self-cleaning antennas, deployable structures, inflatables,
CNT-fiber embedded devices with piezoelectric-mechanical motion for
mountaineering, etc.
[0088] As an example of operation, a few ortho-fabric-material test
coupons of approximately three inches by three inches were applied
with multiple configuration of DMS 300 to test the use of
CNT-fibers as electrodes and the resulting dust removal capability
when the electrodes were applied with a multi-phase AC
voltage-signal.
[0089] FIG. 20 shows a top-view of an example of an implementation
of the DMS 2000 utilizing an ortho-fabric-material 2002 for a
spacesuit and a plurality of CNT-fibers 2004 for the plurality of
conductive-fibers in accordance with the present disclosure. In
this example, the plurality of CNT-fibers 2004 are woven into
ortho-fabric-material 2002 within the shield 2006 that is defined
by the shield area 2008. The plurality of CNT-fibers 2004 are
directed along the first direction 2010.
[0090] In this example, the CNT-fibers of the plurality of
CNT-fibers 2004 were produced from concentrated solutions of
chlorosulfonic acid via wet-spinning. The CNT-fibers were assembled
into twisted, multifilament yarns with a Planetary 3.0 rope-making
apparatus from the Domanoff Workshop of Minsk, Belarus. The yarns
utilized for this example consisted of 28 CNT-filaments plied
together. In this example, the word "yarn" is interchangeable with
"fibers" since each CNT-fiber consisted of 28 CNT-filaments. The
individual CNT-filaments were about 26+/-2 .mu.m in diameter and
had an average linear density of approximately 0.82+/-0.2 tex. The
conductivity of the individual CNT-filaments were about 2.1 MS/m
(specific conductivity was approximately 1390 Sm.sup.2/kg). While
the plied yarns had approximately the same specific conductivity as
individual CNT-filaments, the conductivity of the yarns decreased
to about 1.1 MS/m because the density of the yarns was
approximately 0.8 g/cm.sup.3, compared to the about 1.5 g/cm.sup.3
density of the individual CNT-filaments. In this example, the DMS
2000 was configured to be tested with a three-phase AC power supply
for the input-signal-source (not shown). Similar to FIG. 20, FIG.
21 shows a top-view of an example of another implementation of the
DMS 2100 utilizing the ortho-fabric-material 2002 for a spacesuit
and a plurality of CNT-fibers 2102 for the plurality of
conductive-fibers in accordance with the present disclosure. In
FIG. 21, the plurality of CNT-fibers 2102 are shown as directed in
an angled direction 2104 that is at an angle to the first direction
2010.
[0091] In an example of operation, the DMS 2000 was tested
utilizing an input-signal-source that produced multi-phase AC
voltage-signals that ranged between approximately 600V to 1,200V
with very low current values in the order of micro-amps and had a
frequency of approximately 10 Hz with a square waveform. The tests
were conducted at room temperature and pressure utilizing the
JSC-1A lunar simulant with a size range of approximately 50 .mu.m
to 75 .mu.m and 10 .mu.m to 50 .mu.m. The specifications for the
simulant were developed by Orbital Technologies Corporation of
Madison, Wis. While performing the tests, two methods of depositing
the simulant over the DMS 2000 were utilized. The first method
employed conductive-fiber (i.e., CNT-fibers) activation as the
first step prior to dust deposition (i.e., deposition of the
simulant), after which the simulant was continuously dropped (i.e.,
termed "drop-test") over the DMS 2000 to represent dynamic dust
interacting with the spacesuit during an EVA operation. With the
second method, approximately 10 mg of simulant was deposited over
the shield area on the DMS 2000 covered with the plurality of
CNT-fibers 2004 prior to the CNT-fibers being activated. This
second test method represents a scenario where the dust statically
adheres to the spacesuits during an EVA. In this example, it is
noted that while the AC voltage-signal utilized were on the order
of approximately 600V to 1,200V, the amount of current passing
through the plurality of CNT-fibers 2004 was very low (i.e., on the
order of micro-amps). The results of the tests showed that the DMS
2000 was capable of repelling lunar dust simulant with particle
size between approximately 10 .mu.m to 75 .mu.m in both dynamic and
static dust settings in ambient conditions (i.e., approximate
temperature of 20.degree. C., relative humidity of 68%, and Earth
gravity). As a result, the tests demonstrated positive results for
utilizing the DMS 2000 for repelling lunar dust simulant when
applied with a multi-phase AC voltage-signal. It is noted that
two-phase AC voltage-signals may also be utilized with DMS 2000 and
DMS 2100. As an example, the DMS 2000 and DMS 2100 may utilize an
input-signal-source that produces two-phase AC voltage-signal (with
180.degree. phase shift) that ranges between approximately 600V to
1,200V with very low current values in the order of micro-amps and
has a frequency of approximately 10 Hz with a square waveform.
[0092] In FIG. 22, a flowchart is shown illustrating an example of
an implementation of a method 2200 of dust mitigation performed by
the DMS 1800 in operation in accordance with the present
disclosure. In this example, the DMS 1800 will be assumed to be the
DMS 1800 shown in FIG. 18 that includes the micro-vibratory sensors
and actuators 1600.
[0093] The method begins 2202 by sensing 2204 any dust particles
with the sensors 1802 and 1804 within the fabric-material 1602. If
the sensors 1802 and 1804 detect dust particles on the shield 313
of the fabric-material 1602, the sensors 1802 and 1804 send sensor
data signals 1812 and 1814 to the DMS controller 1801. The DMS
controller 1801 receives 2206 the sensor data signals 1812 and 1814
and, in response, activates the plurality of conductive-fibers
(i.e., the plurality of CNT-fibers 1604) by sending an adjustment
signal 1816 to the input-signal-source 318 that produces 2208 the
AC voltage-signal in response to the adjustment signal 1816. Once
the AC voltage-signal is received 2210 at the plurality of
input-nodes 310 (described in relation to FIG. 3A) of the
fabric-material 1602, the AC voltage-signals are passed to the
plurality of conductive-fibers that corresponding generate 2212 an
electric-field on the front-surface of the fabric-material 1602.
The electric-field corresponding generates 2214 a traveling-wave
that travels along the front-surface of the fabric-material 1602 in
a direction that is traverse to the direction that the
conductive-fibers run along the fabric-material 1602. This
traveling-wave repulses 2216 the dust particles from the shield of
the DMS 1800. In additional, based on the sensor data signals 1812
and 1814, the DMS controller 1801 may also send the
actuation/adjustment signal 1820 to the actuator 1806 to cause the
actuator 1806 to vibrate 2218 under the outermost-layer 1700 of the
fabric-material 1602 in order to assist is losing and removing any
dust from the shield. The process then ends 2220.
[0094] It will be understood that various aspects or details of the
implementations may be changed without departing from the scope of
the disclosure. It is not exhaustive and does not limit the claimed
disclosure to the precise form(s) disclosed. Furthermore, the
foregoing description is for the purpose of illustration only, and
not for the purpose of limitation. Modifications and variations are
possible in light of the above description or may be acquired from
practicing the disclosure. The claims and their equivalents define
the scope of the disclosure.
* * * * *